Azimuth ring printing stamp for maps



Jan. 22, R. BARKER AZINUTH RING PRINTING STAMP PoR MAPS Filed March 7,1949 Patented Jan. 22, A1952 UNITED STATES PATENT OFFICE Ray C. Barker,Denver, Colo. Appueation'March 7, 1949, serial No. 80,020

3 Claims. V l

This invention relates to a rubber stamp, and more"particularly to astamp designed to print a protractor ring or azimuth circle about aselected point upon a map.

Azimuth circles upon an air travel map are printed about the principalair ports upon the map, showing the magnetic compass directions fromthose ports corrected for theA magnetic variation at that particularlocality. It wouldv be impractical and highly confusing to place thesecircles about al1 points upon the map. Occasionally, however, it becomesnecessary for a pilot to orient himself from intermediate'points foremergency landings or for landings off the charted travel beams. Thebearings to the latter pointsv may be obtained visually over the compassneedle, or by radio-compass to available radio broadcasting stations. Itis impossible, however, to draw lines on the map from the locatedcontrol points without azimuth circles about the selected points whichhave also been corrected for# the magnetic needle variation of theparticular-locality.A The principal object of this invention is toprovide a'rotatable rubber azimuth stamp withmeans foralignng the stampIwith relation to map meridians and with means for setting off` themagnetic variations which can be quickly, easily, and vaccurately setover a selected point on an air travel map to print a corrected azimuthabout that point to enable location lines to be accurately drawn fromthe selected points, the intersection of which will give the exactlocation of the plane on the map.

Another object is to provide a rubber stamp which can be moved over amap'without smearing the stamp ink thereon, and which can be placed uponan inking pad without danger of inking any portions except the printingfaces of the type. A vA further object is to provide an air map stampwith a mileage scale so that map distances can be accurately measured onthe map by meansof the stamp.

A still `further object is to provide a transparent air map stamp whichwill not obscure the portions of theY map upon which it is placed, andwhich can be quickly and accurately centered over se lected points onthe map.

'Othervobjects and advantages reside in the'detail. construction of theinvention, which is designed forj simplicity, economy, and efficiency.These will become more apparent from the following description.

In the following detailed description of the nvention, reference is hadto the accompanying drawing which forms a part hereof. Like numeralsrefer to like parts in all views of the drawing and throughout thedescription.

In the drawing:

Fig. l illustrates the improved stamp as it would appear in place upon aconventional air map;

Fig. 2 is an approximately full size plan view of the stamp;

Fig. 3 is a cross-section, taken on the line 3 3, Fig. 2;

Fig. 4 is a similar cross-section, illustrating the stamp in theprojected position, ready to be inked;

Fig. 5 is a horizontal section, taken on the line 5 5, Fig. 3;

Fig. 6 is an enlargement of a portion of the air map of Fig. 1,illustrating the type of impression made by the stamp about a selectedpoint upon the map; and

Fig. 7 is a detail section, taken on the line 1 1, Fig. 2.

A portion of a typical air map is indicated by the numeral I0 on thedrawing, with its north and south meridian lines at 32.

The improved air map stamp is formed from any suitable transparentplastic, such as lumarith or the like, and comprises a relatively thick,square, transparent base block i I having a centra1 stamp opening I2,and provided on its bottom with engraved meridian lines I3 extendingparallel to its two side edges. The usual air travel map is drawn to ascale of l"=15.8 miles, and it is preferred to space the vmeridian lineson the block I I at intervals of ve map miles, and to form the block3.164 inches square to correspond to miles on the map. This spacing ofthe lines I3 and the size of the block make the base block exceedinglyuseful as a scale for measuring distances on the map.

A rotatable, annular index plate I4 is inset in an annular shoulderdepression or counterbore about the top of the stamp opening I2, and isheld therein by means of a top plate I5 having a central opening I6corresponding in size and in alignment with the stamp opening I2 in theblock I I.. `The top plate I5 is cemented or otherwise's'ecured to thetop of the block I I so that the index plate may rotate freelytherebeneath. The index plate I4 is provided With a central opening Ilhaving two oppositely extending key notches I8. It also carries aradially extending index line I9 engraved upon its lower surface.

The base block II is provided with a magnetic deflection scale 25 whichis engraved in the recess below the index plate I4, and upon whichpositions are indicated by the index line IS. Both the scale and theline I9 are clearly visible through the transparent top plate I5.

A rotatable center sleeve 2| passes through the central opening of theindex plate I4. The sleeve is provided with two oppositely extendingkeys 22 which normally rest in the key notches I8 in the index plate I4.The keys 22 do not extend completely to the top of the sleeve 2 I,however, so that if the sleeve is suiciently depressed, the keys willpass from the notches and the sleeve may be rotated independently of theindex plate I4, if desired.

A circular, concentric rubber stamp disc 23 is formed completely acrossthe bottom of the sleeve 2l and projects outwardly thereabout and acrossthe open center thereof. An annular rubber stamp 24 is securedconcentrically to the disc 23. The stamp 24 carries degree markings froma north meridian to form a complete 360 azimuth, as shown in Fig. 6. Acentering opening 25 is formed through the disc 23 at the exact centerof the stamp 24.

A circular top disc 26 is secured upon the top of the sleeve 2l by meansof suitable attachment; screws 21, or in any other desired manner. Thisdisc 26 has a diameter slightly less than the open'- ing I6 in the topplate I5. A conical compression spring 28 is compressed between the topdisc 26 'and the index plate I4 to constantly urge the stamp plate 23upwardly against the index plate I4, as shown in Fig. 3.

The zero or north indication on the azimuth scale 29 is placed so as tobe positioned directly below the index line I9 on the index plate I4when the keys 22 are in the notches I8. The index plate I4 may be lockedin lany pre-set rota-Y tive position by means of a clamping disc 30which is inset in an opening through the top plate I5 so that it willextend over the peripheral edge of the index plate I4. It can be clampedagainst the plate I4 by means of a clamp screw 3| which is threaded intothe base block II.

Operation Referring to the map I0 of Fig. 1, let us assume that a pilottakes a bearing to the town of Shelbyville, and a secondbearing to thetown of Newcomb on the map I0, and that the magnetic compass variationfor this particular locality is 11 west. The top disc 26 is rotated toplace the index line I9 below the 11 Westf marking on the scale 20, andthe scale is locked by means of the screw 3|. The centeringopening 25 isnow placed over the town of Shelbyville on the map, with the meridianlines I3 lying on or positioned parallel to the map meridians 32, andthe top disc 26 is depressed to print a magnetically corrected azimuthcircle around Shelbyville, as shown in Fig. 1.

\ The process is now repeated over the town of Newcombf as shown in Fig.l, to produce the azimuth circle thereabout, as shown in Fig. 6. A lineis now drawn on the map from Shelbyyille, as indicated by the line A,and from Newcomb, as indicated by the line B. The lines are drawnthrough the proper positions on the printed protractor circles tocorrespond to the bearings taken to the towns from the plane. The pointwhere the two lines A and B intersect on the map gives the position ofthe plane, as indicated at C in Fig. 1.

- The stamp 24 may be inked on an ordinary stamp pad. For inking, thetop disc 26 is depressed to force the keys 22 'out of their notches I8,and the disc is rotated slightly to place the keys 22 below the indexplate I4. This locks the stamp 24 below the surface of the block II, asshown in Fig. 4, so that it may be impressed against a rubber stamp padwithout inking the block II. rotated until the keys 22 align with thenotches I8 to allow the spring 28 to snap the device back to the workingposition of Fig. 3.

While a specific form of the improvement has been described andillustrated herein, it is to be understood that the same may be varied,within the scope lofthe appended claims, without departing from thespirit of the invention.

Having thus described the invention, what ls claimed and desired securedby Letters Patent is:

l. An air map stamp comprising: a relatively thick, rectangular baseblock of transparent material; meridian linesA engraved on said blockparallel to the two side edges thereof, said lines being visible throughsaid block; a central stamp opening extending vertically through saidblock; a transparent rotatable index plate inset'in a oounterbore at thetop of said opening; a transparent top plate on said block extendingover said index plate to maintain the latter in its counter-- bore, saidtop plate and said index plate having centrallyl positioned openings; adegree Scale carried by said block belowsaid index plate so as to bevisible through the latter; an indicating line on said index plate oversaid scale to indicate positions on the latter; and an annular azimuthcircle printing stamp mounted concentrcally in said openings andarranged to rotate with said index plate.

2. An air map stamp comprising: a. relatively thick, rectangular baseblock of transparent material; meridian lines engraved on said blockparallel to the two side edges thereof, said lines being visible throughsaid block; a central stamp opening extending vertically through saidblocki a transparent rotatable index plate inset in a oounterbore at thetop of said opening; a transparent top plate on said block extendingover said index plate to maintain the latter in its oounterbore, saidtop plate and said index plate having centrally positioned openings; adegree scale carried by said block below said indexrplate so as to bevisible through the latter; an indicat-v ing line on said index plateover said scale to indicate positions on the latter; a tubular sleevepassing concentrically through the'opening's in said top and indexplates; va stamp plate on the bottom of said sleeve; anannular rubberstampl carrying an azimuth circle concentrically posi. tioned on thebottom of said stamp plate; a spring urging said stamp plate upwardly;and means for communicating the rotation of said sleeve to'said indexplate. A

3. An air map stamp comprisin'g: a relatively thick, rectangular baseblock of transparent material; meridian lines engraved on said blockparallel to the two side edges thereof, said lines being visible throughsaidblock; a central stamp opening extending vertically through saidblock; a transparent rotatable index plate inset Ain a oounterbore atthe top of said opening; a trans-4 parent top plate on said vblockextending over said index plate to maintain the latter in itscounterbore, said top plate and said index platel having centrallypositioned openings; a degree scale vcarried by said block below saidindex 'plate indicate positions on the latter; a tubular sleeve Wheninked, the top disc 26 is simply' passing ooncentrically through theopenings in said top and index plates; a stamp plate on the bottom ofsaid sleeve; an annular rubber stamp carrying an azimuth circleconcentrically positoned on the bottom of said stamp plate; a top disc:mounted upon the top of said sleeve; a, spring compressed between saidtop disc and said index plate to urge said stamp upwardly; and keysprojecting from said sleeve into receiving notches in said index plateto communicate the rotation of the former to the latter, said keysterminating in spaced relation to said top disc so as to pass from saidnotches when said sleeve is forced downwardly against the action of saidspring so as to means ausw said sleeve u be rotated maependenuy of saidindex plate. f1

RAY C. BARKER..

REFERENCES CITED` The following references are of record in the ille ofthis patent:

UNITED STATES PATENTS

